From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761538AbZBLXOR (ORCPT ); Thu, 12 Feb 2009 18:14:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756773AbZBLXOA (ORCPT ); Thu, 12 Feb 2009 18:14:00 -0500 Received: from e5.ny.us.ibm.com ([32.97.182.145]:44323 "EHLO e5.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750802AbZBLXN7 (ORCPT ); Thu, 12 Feb 2009 18:13:59 -0500 Subject: Re: [RFC v13][PATCH 00/14] Kernel based checkpoint/restart From: Dave Hansen To: Matt Mackall Cc: Ingo Molnar , Andrew Morton , orenl@cs.columbia.edu, linux-api@vger.kernel.org, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, hpa@zytor.com, Thomas Gleixner , Cedric Le Goater , Pavel Emelyanov , Alexey Dobriyan In-Reply-To: <1234479924.3152.13.camel@calx> References: <1233076092-8660-1-git-send-email-orenl@cs.columbia.edu> <1234285547.30155.6.camel@nimitz> <20090211141434.dfa1d079.akpm@linux-foundation.org> <1234462282.30155.171.camel@nimitz> <1234467035.3243.538.camel@calx> <1234479457.30155.214.camel@nimitz> <1234479924.3152.13.camel@calx> Content-Type: text/plain Date: Thu, 12 Feb 2009 15:13:53 -0800 Message-Id: <1234480433.30155.226.camel@nimitz> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2009-02-12 at 17:05 -0600, Matt Mackall wrote: > On Thu, 2009-02-12 at 14:57 -0800, Dave Hansen wrote: > > > Also, what happens if I checkpoint a process in 2.6.30 and restore it in > > > 2.6.31 which has an expanded idea of what should be restored? Do your > > > file formats handle this sort of forward compatibility or am I > > > restricted to one kernel? > > > > In general, you're restricted to one kernel. But, people have mentioned > > that, if the formats change, we should be able to write in-userspace > > converters for the checkpoint files. > > I mentioned this because it seems like a key use case is upgrading > kernels out from under long-lived applications. The key users as I envision it aren't really kernel hackers who are always running 2.6-next and running radically different kernels from moment to moment. :) Distros are pretty picky about changing things internal to the kernel during errata updates or even service packs. While that can be a pain for some of us developers trying to get features and fixes in, it is a godsend for trying to do something like process migration across an update. My random speculation would be that for things that if a kernel upgrade can be performed with ksplice (http://www.ksplice.com/) -- the original non-fancy version at least -- we can probably migrate across the upgrade. -- Dave From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: [RFC v13][PATCH 00/14] Kernel based checkpoint/restart Date: Thu, 12 Feb 2009 15:13:53 -0800 Message-ID: <1234480433.30155.226.camel@nimitz> References: <1233076092-8660-1-git-send-email-orenl@cs.columbia.edu> <1234285547.30155.6.camel@nimitz> <20090211141434.dfa1d079.akpm@linux-foundation.org> <1234462282.30155.171.camel@nimitz> <1234467035.3243.538.camel@calx> <1234479457.30155.214.camel@nimitz> <1234479924.3152.13.camel@calx> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1234479924.3152.13.camel@calx> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matt Mackall Cc: Ingo Molnar , Andrew Morton , orenl-eQaUEPhvms7ENvBUuze7eA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org, Thomas Gleixner , Cedric Le Goater , Pavel Emelyanov , Alexey Dobriyan List-Id: linux-api@vger.kernel.org On Thu, 2009-02-12 at 17:05 -0600, Matt Mackall wrote: > On Thu, 2009-02-12 at 14:57 -0800, Dave Hansen wrote: > > > Also, what happens if I checkpoint a process in 2.6.30 and restore it in > > > 2.6.31 which has an expanded idea of what should be restored? Do your > > > file formats handle this sort of forward compatibility or am I > > > restricted to one kernel? > > > > In general, you're restricted to one kernel. But, people have mentioned > > that, if the formats change, we should be able to write in-userspace > > converters for the checkpoint files. > > I mentioned this because it seems like a key use case is upgrading > kernels out from under long-lived applications. The key users as I envision it aren't really kernel hackers who are always running 2.6-next and running radically different kernels from moment to moment. :) Distros are pretty picky about changing things internal to the kernel during errata updates or even service packs. While that can be a pain for some of us developers trying to get features and fixes in, it is a godsend for trying to do something like process migration across an update. My random speculation would be that for things that if a kernel upgrade can be performed with ksplice (http://www.ksplice.com/) -- the original non-fancy version at least -- we can probably migrate across the upgrade. -- Dave -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id C62A06B0095 for ; Thu, 12 Feb 2009 18:13:59 -0500 (EST) Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e8.ny.us.ibm.com (8.13.1/8.13.1) with ESMTP id n1CN75J1026668 for ; Thu, 12 Feb 2009 18:07:05 -0500 Received: from d01av01.pok.ibm.com (d01av01.pok.ibm.com [9.56.224.215]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v9.1) with ESMTP id n1CNDvh2172530 for ; Thu, 12 Feb 2009 18:13:57 -0500 Received: from d01av01.pok.ibm.com (loopback [127.0.0.1]) by d01av01.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n1CNDuww028796 for ; Thu, 12 Feb 2009 18:13:57 -0500 Subject: Re: [RFC v13][PATCH 00/14] Kernel based checkpoint/restart From: Dave Hansen In-Reply-To: <1234479924.3152.13.camel@calx> References: <1233076092-8660-1-git-send-email-orenl@cs.columbia.edu> <1234285547.30155.6.camel@nimitz> <20090211141434.dfa1d079.akpm@linux-foundation.org> <1234462282.30155.171.camel@nimitz> <1234467035.3243.538.camel@calx> <1234479457.30155.214.camel@nimitz> <1234479924.3152.13.camel@calx> Content-Type: text/plain Date: Thu, 12 Feb 2009 15:13:53 -0800 Message-Id: <1234480433.30155.226.camel@nimitz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Matt Mackall Cc: Ingo Molnar , Andrew Morton , orenl@cs.columbia.edu, linux-api@vger.kernel.org, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, hpa@zytor.com, Thomas Gleixner , Cedric Le Goater , Pavel Emelyanov , Alexey Dobriyan List-ID: On Thu, 2009-02-12 at 17:05 -0600, Matt Mackall wrote: > On Thu, 2009-02-12 at 14:57 -0800, Dave Hansen wrote: > > > Also, what happens if I checkpoint a process in 2.6.30 and restore it in > > > 2.6.31 which has an expanded idea of what should be restored? Do your > > > file formats handle this sort of forward compatibility or am I > > > restricted to one kernel? > > > > In general, you're restricted to one kernel. But, people have mentioned > > that, if the formats change, we should be able to write in-userspace > > converters for the checkpoint files. > > I mentioned this because it seems like a key use case is upgrading > kernels out from under long-lived applications. The key users as I envision it aren't really kernel hackers who are always running 2.6-next and running radically different kernels from moment to moment. :) Distros are pretty picky about changing things internal to the kernel during errata updates or even service packs. While that can be a pain for some of us developers trying to get features and fixes in, it is a godsend for trying to do something like process migration across an update. My random speculation would be that for things that if a kernel upgrade can be performed with ksplice (http://www.ksplice.com/) -- the original non-fancy version at least -- we can probably migrate across the upgrade. -- Dave -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org